Power semiconductor modules containing solid-state switching devices such as IGBTs or Power-MOSFETs are used in various power electronics applications to switch or rectify electric currents. An important and fast growing application are converter systems for electric or hybrid electric vehicles. A typical six-pack module (containing three half-bridges with two semiconductor switches) for such applications may have a voltage rating of up to 1200 V and a current rating of several 100 A.
Besides the high-current power terminals by which the power semiconductor module is connected to the AC (e.g. motor) and DC (e.g. battery) side, a six-pack or half-bridge power semiconductor module usually also has several auxiliary terminals for connection to a gate driver board that contains a driver circuit which controls the different semiconductor devices in the power semiconductor module and/or may detect fault situations. A typical six-pack power semiconductor module may have up to ten such auxiliary connections per half-bridge, that is, 30 connections for a full six-pack inverter module.
Technologies commonly used for auxiliary terminal connections are screw connections, solder pin connections and press-fit connections.
Another preferred solution especially for automotive power modules is epoxy mold encapsulation, which can have benefits in terms of high-temperature capability, humidity resistance, cost, and high-volume manufacturability.
Unfortunately, the common epoxy molding processes for such semiconductor encapsulation (transfer and epoxy molding) are not compatible with pins sticking out vertically from the power semiconductor module as in the housing-based power semiconductor modules.
Transfer-molded power modules with lead-frame terminals for power and auxiliary connections on the side of the module usually have rather long auxiliary connections, which may imply larger inductances and less favorable switching behavior. Furthermore, if a single lead frame is to be used for both power and auxiliary terminals (which has advantages regarding the manufacturing of the power module), then expensive press-fit material such as CuNiSi has to be used also for the power terminals, which otherwise could be made of cheaper copper material.
WO 2014 166692 A1 and US 2009 146272 A1 show a semiconductor module with receptacles for press-fit pins molded into a top side of a molded encasing.